Wired News has reported that General Motors, DaimlerChrysler, and Ford are working on diesel-hybrid prototypes.

According to Charlie Freese, executive engineering director at GM Powertrain:

… many factors that make diesel engines more efficient include operating unthrottled and more efficient oxidizing of fuel. Diesel engines also have a higher compression ratio, and the heavier diesel fuel has a higher energy density … diesel and hybrid technologies have synergies because hybrid systems reduce fuel consumption by relying on the electric motor while idling and during acceleration of stop-and-go traffic. Diesel engines are optimized for hauling heavy loads and for steady-speed highway driving.

Now, longtime Grist readers will know that Umbra has had some harsh words when it comes to diesel (but not biodiesel and SVO though). While responding to a reader asking if a higher gas mileage diesel car is better than a less-particulate-emitting gasoline engine, she offered the following analogy:

Let’s recall some stale high school stereotypes: the cruel football player and the catty cheerleader. Diesel oil is the football player — big, strong, lunk-headed, unwashed, and mean. Gasoline is the cheerleader: slimmer, well-groomed, and socially manipulative. They’re both toxic to the school atmosphere, but people are more inclined to avoid the bully, because he is more immediately physically hazardous.

Umbra sums up her article by saying, “… all diesel cars are considered ‘inferior’ in the American Council for an Energy-Efficient Economy’s Green Book.” But what would Umbra think of a diesel hybrid engine? Here’s what Dan Benjamin, an analyst at ABI Research, had to say:

“Can hybrid engines help (reduce) diesel emissions? Absolutely,” Benjamin said. Although diesel vehicle manufacturers will likely add filters or catalytic converters to reduce emissions, “hybrid systems can cut emissions by eliminating situations where NOx (nitrogen oxide) emissions are at their very worst,” according to Benjamin. Meeting California’s tougher emissions requirements, which have been adopted by four other states, presents more of a challenge, Benjamin said.

So maybe those nasties Umbra is worried about won’t be as much as a concern. What say you?